1. Technical Field of the Invention
The present invention relates to the manufacture of sheet form articles having paper webs, such as paper or wet non woven cloths or the like, and in particular, relates to a method and device for the manufacture of paper webs, and further relates to an exchange method for forming wires and the like.
2. Background Art
In conventional paper web manufacturing methods, various types of specialized formers were employed using fourdriniers and cylinder formers as a base, such as on-top formers, twin wire formers, inclined wire formers, suction cylinder formers, and the like. Furthermore, in conventional cylinder formers, as the speed increased, centrifugal force tended to operate, and the paper web formation became disordered, so that it was necessary to either apply a suction force to the inner surface of a cylinder mold or to apply a pressurizing force to the outer surface of the cylinder mold in order to reach a balance with the centrifugal force. For this reason, various types of suction, pressurization, and depressurized or pressurized cylinder formers have been developed.
In all of these depressurized or pressurized cylinder molds a backing wire (commonly having a mesh within a range of 8-16) and a face wire (commonly having a mesh within a range of 50-80) are wound and affixed using silver solder to the outer circumference of a cylinder having a suction roll structure; however, fibers present in the paper stock, resin, sizing agent, filler and the like tend to be deposited in the gaps in the wires. Accordingly, particularly during times when paper stock is employed to which is added a large amount of filler (titanium dioxide, talc, calcium carbonate), the filler is the source of blockages in the openings of the wire or the suction roll, so that it is necessary to repeatedly stop the machinery and to clean the wire or the suction roll, or to exchange the wire, so that this creates a problem in that the operational efficiency declines. In particular, when suction rolls are employed, it is necessary to remove the roll cell, and to open the blockages in the opening one by one by inserting a hand-operated drill into the holes of the roll cell, so that the operational efficiency declines dramatically. For this reason, cylinder formers normally employ almost no filler, and are employed in the making of paper such as tissue paper, paper board, filter paper, or paper for electrolytic condensers.
However, in the case of paper for certificates, various types of paper for gold notes, paper for bank notes, and the like, there are limits to the expressive power of watermarks formed by suction box parts, or dandy rolls on a fourdrinier, so that it is still the case that watermarks produced by methods employing cylinder formers are employed.
However, when a method using a cylinder former to make watermarked papers is employed, the surfaces must always be kept perfectly circular, and the structure must be strong, so that both the face wire and backing wire are completely silver soldered to both end parts of the cylinder mold or the main body of the dandy roll, and removal thereof is difficult. Accordingly, it is difficult to prepare a plurality of varied cylinder molds or dandy rolls corresponding to the finished dimensions of the watermark design or the sheets, to exchange the cylinder molds with each respreading, and in order to maintain cleanliness, to store these in a storehouse or the like, and as a result, it is not merely the case that the exchange of the cylinder molds or the dandy rolls is a time consuming process, but the efficiency of use of the cylinder molds or dandy rolls is low, and there is also a problem in that a large amount of space is required for the storage of the cylinder molds or the dandy rolls.